-Showing your wealth (in the same way as men in some societies show off being able to feed many fat wives)

– The Chinese and Japanese philosophy of your mystic energy (気-ki, or chi in Chinese) being centred on your belly

– Wanting to look like rikishi (sumo wrestlers), the ultimate Japanese men

– Just to make a distinction between the female shape (also in a kimono and with breasts flattened, but with a big obi emphasizing any bumps at the back) and the male shape (obi worn under the belly to emphasize its shape at the front)

– Some kind of cultural universal of manliness that has been lost in the West (see paintings of Henry VIII of England for examples)